1. Field of the Invention
The present invention relates to a distance calculation system between a movable body and a fixed subject, and more specifically to, for example, a distance calculation device and a calculation program for calculating the correct distance between a traveling vehicle on a road and a subject based on the amount of status of a vehicle such as the elevation angle between a traveling vehicle and a subject, an azimuth angle, the velocity and the yaw rate of a vehicle, etc.
2. Description of the Related Art
The car navigation technology of guiding a driver depending on the current position of a vehicle and the destination has made much progress and has become widespread by detecting the position of a vehicle using a map database and a GPS (global positioning system). In this system, based on the information about the latitude and the longitude obtained by the GPS, the position of the pertinent vehicle is superposed and displayed on the map, and the distance to a crossing, etc. is calculated.
An example of the above-mentioned conventional technology is disclosed by the following patent document.
Patent Document
Japanese Patent No. 3381312 (P3381312) “Navigation Apparatus”
This patent document discloses the technology of recognizing a subject whose position can be designated according to map information, calculating the distance between the subject and the pertinent vehicle based on the running distance of the vehicle between two points of time, and the elevation angle from each point to the same subject, and correcting the position of the pertinent vehicle.
However, in this conventional technology, only the linear distance to a traffic signal can be calculated, and there is the problem that an error occurs when the distance is calculated on the practical traveled distance on the road which is often a curved road and there is no traffic signal in the traveling direction of the pertinent vehicle.